Device for starting gas turbines



Dec. 19, 1967 l. M. MANSSON ETAL DEVICE FOR STARTING GAS TURBINES Filed March 7, 1966 IVAR MARTIN MANSSON and FRANS ERIC OSSIAN OSTMAR INVENTORJ BY ERIC v. MuNsoN,

Attorney United States Patent 3,358,909 DEVICE FOR STARTING GAS TURBINES Ivar Martin Mansson and Frans Eric Ossian Ostmar, Finspong, Sweden, assignors to Stal Laval, Finspong, Sweden, a corporation of Sweden Filed Mar. 7, 1966, Ser. No. 532,460 Claims priority, application Sweden, Apr. 20, 1965, 5,075/ 65 4 Claims. (Cl. 230-45) The present invention relates to a device for starting gas turbines with a low pressure and a high pressure compressor which, through an air duct, are connected in series with and driven by a low pressure and a high pressure turbine respectively by means of a compressed air driven jet located between the compressors.

It is one of the objects of the invention to provide a substantially simplified starting device as compared to those known in this art and in which the jet has been connected to a line for starting air connected in parallel with the air duct; and to provide for an efficient apparatus.

More particularly, the invention contemplates the provision of a jet that is located centrally in the air duct and with its nozzle passing through a valve, the valve being positioned straight across the air duct and including hinged flaps which, when the ejector is in operation, are intended to be closed to prevent the backflow of compressed air introduced by the jet and which, when the compressors begin to suck air, are intended to be open to allow passage to the flow of air from the low pressure compressor.

With these and other objects to be hereinafter set forth in view, we have devised the arrangement of parts to be described and more particularly pointed out in the claims appended hereto.

In the accompanying drawing wherein an illustrative embodiment of the invention is disclosed,

FIG. 1 is a longitudinal sectional view showing the improved starting device, and

FIG. 2 is a cross section along the line IIII in FIG. 1, showing the flaps in lowered position.

From a low pressure compressor 11, air is carried through a duct 1 to the high pressure compressor indicated at 2. Centrally and axially arranged within the duct 1 is a jet 3, or air ejector, to which air is delivered through a line 4 from a pressure vessel not shown, or from another source.

The nozzle of the jet 3 passes through a valve that is positioned straight across the air duct 1, such valve including hinged or swingable flaps 5 and 6 provided with arcuate recesses or notches 7 and 8 to facilitates the sealing of the flaps around the periphery of the nozzle of the jet when the flaps are in their closed position as shown in FIG. 2.

The diffuser section of the jet in advance of the valve consists of parts arranged in series to thereby form an articulated unit. Through such an arrangement, movements due to temperature variations, between the inlet r 3,358,909 Ice Patented Dec. 19, 1967 section of the compressor 2 and the air duct 1 in advance of the jet are permissible, since the articulated jet is able to compensate for such movements,

When the gas turbine is to be started, the jet 3 is supplied with compressed air by means of the line 4, causing air to be sucked through the low compressor and duct 1 to the high pressure compressor 2. The valve flaps 5 and 6, which are controlled by pressure-medium actuated pistons 9 and 10 are thereby held closed, as shown in FIG. 2, preventing the backflow of compressed air that has been introduced by way of the jet 3. Air from the jet 3 passes through the high pressure compressor 2 and also through the high pressure and low pressure turbines and such air then acts as a driving medium to set the rotors of the turbines in action. The low pressure compressor also receives rotational assistance from the air that is sucked through it. When the gas turbine starts and begins to suck air, the flaps 5 and 6 are opened to permit the passage of air in the duct space around the jet 3.

Having thus described an embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claims.

What we claim is:

1. A device for starting gas turbines with a low pressure and a high pressure compressor, said compressors being connected in series by means of an air duct, a compressed air jet arranged between the compressors, said jet being located centrally in the air duct and providing spacing between it and the wall of the duct, hinged valve flaps operable across the air duct around the jet, said flaps when closed being effective to close the space be tween the jet and the interior of the duct when the jet is in operation, to thereby prevent the backflow of the compressed air introduced by the jet and which when the compressors begin to suck air, are opened to allow passage to the flow of air from the low pressure compressor.

2. A device according to claim 1, and in which the flaps are provided with recesses for sealing around the jet when the flaps are in their closed position.

3. A device according to claim 1, wherein the ditfuser section of the jet in advance of the flaps consists of parts arranged in series to form an articulated unit.

4. A device according to claim 1 in which the flaps are controlled by the action of pistons.

References Cited UNITED STATES PATENTS 1,045,961 12/ 1912 De Ferranti 230-45 X 2,822,665 2/1958 Nicolin 230-45 X 3,056,539 10/1962 Pullin 23045 3,238,721 3/1966 Brandes et a1. -3914 X 3,239,131 3/1966 Whyte 230-45 ROBERT A. OLEARY, Primary Examiner. W. J. KRAUSS, Assistant Examiner. 

1. A DEVICE FOR STARTING GAS TURBINES WITH A LOW PRESSURE AND A HIGH PRESSURE COMPRESSOR, SAID COMPRESSORS BEING CONNECTED IN SERIES BY MEANS OF AN AIR DUCT, A COMPRESSED AIR JET ARRANGED BETWEEN THE COMPRESSORS, SAID JET BEING LOCATED CENTRALLY IN THE AIR DUCT AND PROVIDING SPACING BETWEEN IT AND THE WALL OF THE DUCT, HINGED VALVE FLAPS OPERABLE ACROSS THE AIR DUCT AROUND THE JET, SAID FLAPS WHEN CLOSED BEING EFFECTIVE TO CLOSE THE SPACE BETWEEN THE JET AND THE INTERIOR OF THE DUCT WHEN THE JET IS IN OPERATION, TO THEREBY PREVENT THE BACKFLOW OF THE COMPRESSED AIR INTRODUCED BY THE JET AND WHICH WHEN THE COMPRESSORS BEGIN TO SUCK AIR, ARE OPENED TO ALLOW PASSAGE TO THE FLOW OF AIR FROM THE LOW PRESSURE COMPRESSOR. 